Control for controllable pitch propellers



April 25, 1961 s. l.. GILLESPIE CONTROL FOR CONTROLLABLE PITOH PROPELLERS 2 Sheets-Sheet 1 Original Filed Feb. 24, 1954 NO- mo- F: O-

April 25, 1961 s. L. GILLESPIE 2,981,340 CONTROL FOR CONTROLLABLE FITCH PROPELLERS Original Filed Feb. 24, 1954 2 Sheets-Sheet 2 Solrlgj Lockwood @JMJ/D@ adm? United States Patent O CONTROL FOR CONTROLLABLE PITCH PROPELLERS Sidney Lockwood Gillespie, Rockford, Ill., assignor to Woodward Governor Company, Rockford, Ill., a corporation of Illinois Original application Feb. 24, 1954, Ser. No. 412,324,

now Patent No. 2,878,880, dated Mar. 24, 1959. Divided and this application Apr. 17, 1958, Ser. No. 729,163

4 Claims. (Cl. 1`70-160.32)

This invention relates generally to controllable pitch propellers adapted to be adjusted through forward and reverse pitch ranges by a selectively controllable power servo.

The general object is to associate with the pitch servo a new and improved power actuated stop mechanism operable selectively to condition the servo for operation through forward or reverse pitch ranges.

The invention also resides in the novel manner of positioning the stop mechanism hydraulically and by remote control.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which Figure 1 is a schematic view and circuit diagram of a propeller and pitch controller embodying the novel features of the present invention.

Fig. 2 is a fragmentary schematic view showing still another position of the servo stop.

In the drawings, the invention is shown as a control for regulating from a point of remote control such' as the pilot house of a ship the pitch of the ship propeller which is driven through a shaft 11 by a prime mover 12.

The propeller shown schematically herein comprising blades 18 journaled on the outer end of the shaft 11 and carrying cranks 19 connected to the end of a rod 20l disposed within the shaft. By adjusting the rod endwise, the blades may be swung in opposite directions away from a flat or zero pitch (Fig. l) and into forward or reverse pitch ranges -to obtain various angles for propelling the ship forwardly or backwardly.

The adjustment may be effected by a power servo herein `shown as a piston 21 and a cylinder 22 supplied with pressure uid under the control of a valve 23 whose plunger 24 is pivotedat one end of a lever 25. One end of the latter is connected at 25a to the rod 20 while the other end is joined by suitable linkage 25h Ito a pitch control element or lever 26 fulcrumed at 27 intermediate its ends and swingable between positions 28 and 29 to produce maximum forward and reverse pitch of the propeller blades. The latter are at llat pitch when the element 26 is in an intermediate or centered position 30.

When the valve plunger 24 is moved out of the centered position shown in Fig. 1, pressure iluid from a high pressure source P will be admitted to the corresponding end of the cylinder 22 to increase the propeller pitch, the other cylinder end being drained. The movement continues until the valve is recentered by the restoring motion transmitted back through the lever 25. With this follow-up arrangement, the pitch of the propeller blades closely follows changes in the position of the control element 26.

Movement of the pitch control member 26 between maximum pitch positions 28 and 29 in the forward and reverse directions of propulsion of the ship and through 2,981,340 Patented Apr. 25, 1961 the flat pitch position 30 is elfected by a servo 98 herein shown as of the rotary type having a vane type piston 99 fast on a shaft 100 and swingable around the interior of a casing 101 in response to pressure variations in chambers 102 and 103 on opposite sides of the vane. Preferably, the motion of the servo shaft is transmitted to the pitch adjusting element 26 to provide for greater increments of pitch adjustment for a given angular displacement of the shaft when the propeller is at low pitch. This is accomplished by a properly contoured cam 104 fast on the shaft and bearing against a follower 105 on the end of the adjusting lever 26 which is held against the cam by a suitable spring 26'. v In the at pitch position of the parts shown in Fig. l, the roller 105 engages the intermediate part of the cam surface. As the cam turns clockwise, the rise of its' sur-V face swings the pitch control lever 26 into a range for producing forward propulsion of the ship. Similarly, as the cam turns counterclockwise from the flat pitch position, the follower 105 rides a fall on the cam surface thereby shifting the control lever into the reverse pitch range, that is, for propellingthe ship backwardly. It will be observed that the vane 99 constitutes a piston element of a double range servo, which adjusts the propeller pitch to one side or the other of zero for forward or reverse propulsion of the ship by the admission of pressure uid selectively to the chambers 102 and 103.

Fluid at the desired pressure is supplied from a source P above described and delivered to the servo 98 through a conduit 106 (Fig. l).

In accordance with the present invention, the pitch adjusting or load control servo 98 is conditioned for operation in the proper pitch range automatically as an incident to a manual selection made by swinging of a control lever 78 which may be located in the pilot house and is preferably used to control the selective energization of the pitch adjusting servo 98. The selection of the pitch range is effected in the present instance by-an auxiliary servo 109 energizjtble selectively by remote control of the lever '78 and operating on the shaft 100 through a stop coupling 110 to confine the operation of the servo 98 to the pitch range selected by the ships pilot. Herein, the servo 109 comprises a piston element or vane 111 fast on a shaft 112 and swingable in an arcuate chamber 113 through a range equal to the length of the individual forward and reverse ranges f and r of the servo 98. The vane 111 is of substantially larger area, about twice in the present instance, than the vane 99 so that the servo 109 is capable of overriding the servo 98 when supplied with pressure uid from the same supply 106. Fluid from lthe latter is admitted to either side of the piston through conduits 114 and 115 leading into opposite ends of the chamber 113.

The stop coupling 110 is operated by the servo 109 to change the operating range of the pitch servo 98. For this purpose, the shafts 100 and 112 are disposed end to end and stops 116 and 117 are fixed on the end of the shaft 112 for coaction with an arm 118 fast on the adjacent end of the shaft 100. The stops comprise arcuate lugs 119 rigid with and projecting from a support in the form of a block 119a and lying in the plane of the arms and with their opposed sides forming the stops 116 and 117 angularly spaced apart to correspond -to the forward pitch range f of the servo 98. Similarly, the spacing of the other lug sides equals the length of the other or reverse pitch range. When pressure is applied to the conduit 114 the vane 111 will be held against one end wall of the chamber 113 thus positioning the stops 116, 117 as shown in Fig. 1 to condition the servo 98 for pitch adjustment in the forward direction only. Now, if the conduit 114 is drained and pressure is applied to the other end of the chamber 113 through the conduit 115,

thevane 111 andthestopswill be turned counterclock- Wise against the other end wall 120 of ythe chamber 113. With the stops thus held by a force greater than that capable of being exerted by the servo 98, the vane 99 of vthe lattercan move back and forth only in the right end 103 of the servo cavity and thus adjust the pitch controlrlever within the reverse range r.

The delivery of energy to the servos 98and 109 t0 energize .the latter in the proper direction selected by the control lever 78 is controlled by a transfer device 122 preferably disposed adjacent the servo and having a member 125 movable back and forth between forward (Fig. 1) and reverse (FignZ) positions. Where, as here, fluid pressure servos are used, the transfer deviceptakes the form of a valve having a ported casing 124 and a plunger 125 slidable therein and having lands coacting with the different ports in the casing. -A compression spring (not shown) acts against one end of the plunger 125 to urge the latter into the forward position shown in full in Fig. l. The plunger is shifted to the reverse position shown in Fig. 2 by a fluid servo 127 at the other end of the valve comprising a piston 128 having a rod that bears against the plunger and is slidable in a cylinder 129 whose length determines the stroke of the plunger.

Pressure fluid such as compressed air from a source 80 is applied to the head end of the cylinder 129 through a conduit 130 which extends to the pilot house of the ship and communicates with the outlet port 133 of a valve 131. The latter includes a plunger 132 movable from closed position (Fig. l) to open position in which the port 133 is uncovered by a land 134. The valve stem is urged toward and constitutes the follower of cam surfaces 135 and 136 which herein are formed on the side of a cam 83. The surface 135 permits the plunger 132 to be held in valve closed position while the lever 78 is disposed between idle position (Fig. l) and full forward speed position, the servo 127 then remaining deenergized. When the lever is swung clockwise out of idle position (see Fig. 2), the surface 136 depresses the plunger 132 to open the valve and admit compressed air from the supply line 80 to the servo 127. The piston 128 is thus moved to shift the transfer valve plunger to the reverse position (Fig. 2) where it remains until the lever 78 is again returned to idle position or beyond. As a result, the valve plunger moves back to the position shown in Fig. 1 thus interrupting the connection to the air supply and releasing the air from the cylinder 129 so as to allow .the spring 126 to return the transfer valve plunger 125 to the forward pitch position (Fig. l).

In both the forward and reverse positions of the transfer valve (Figs. l and 2), the fluid pressure source 106 communicates with a space 138 between two of the plunger lands and therefore with a passage 139 leading to a port 140 in the valve casing. In the forward position ofthe plunger (Fig. l), the port 140 is connected through a space 141 to the conduit 114 leading to the upper end of the stopractuating chamber 113. At the same time, the other passage 115 of this servo registers with an annulus 142 of the plunger 125 at the end of an axial passage 143 which communicates continuously with a drain space 144 at the end of the valve cylinder. The drain passage 143 also communicates with an annular space 137 intermediate the ends of the plunger.

In the other or reverse position (Fig. 2) of the transfer valve, the connections of the stop servo 109 are reversed, the passage114 registering with .the drain passage 143 While the port at the end of the passage 115 registers with the space 141 and thus with the pressure supply passage 139. As a result, pressure fluid is admitted to swingl the vane 111 counterclockwise to its other limit position against the wall 1128 as shown in Fig. 2.

The transfer valve controls the directions of ow of pressure fluid to and from the different chambers 102 and 103 of the pitch adjusting servo 98 whose passage 108 terminates in a port in the valve casing and registers 4. with a plunger space 145 which, in the forwardrposition of the plunger (Fig. 1) communicates with a port at the end of the passage 146 and, in the reverse position (Fig. 2) registers with a port at the end of a passage 151. The other servo passage 107 has two branches terminating at ports 147 and 148 which are spaced along the valve casing, the former registering with a plunger space 149 in both positions of the valve whileV theI latter registers with a space 150 in both positions of the valve. Thus by deenergization and energization of the servo 127, the transfer valve plunger 125 isdisposed in a forward position (Fig. l) in which the passages 146 and 151 are connected to the servo passages 108 and 107 or a reverse position (Fig. 2) in which the connections are reverse, the passages 146 and 151 then being connected to the servo passages 107 and 108 respectively.

The hand lever 78 which selects the desired range of the propeller pitch adjustment is also utilized to control the low of pressure uid to the servo 98 and thereby v,determine the desired pitch. To this end, camsurfaces 90 vand 91 on the cam 83 are arranged to actuate a valve by which pressure fluid from the supply line 139 `is directed to the proper side of the vane `99 of the servo 98.

Energization of thepitch servo 98fis `controlled by lands 187V and 188 in the valve 18S cooperatingwith ports -189 and 190 in the valve casing which communicates with the pressure lluid supply line l139. The ports lead through passages 146 and 151 to the pitch servo.

Herein, the stem of the pilot valve is pivotally connected at 193 to a lever 194 bearing near its other end against a follower of the cam 83 and urged downwardly by spaced compression springs 195. To make the movements of the pitch control member 26 follow proportionately the position changes of the lever 194, the movements of the member are transmitted back to the lever 194, -the restoring connectionherein taking the form of a rod 196 bearing at one end 199 against the same side of the lever as the stem 182 and at a point located between the valve 185 and the stem and in alinement with one of the springs `195. A roller 197 on the other end of the rod rides a heart shaped cam 198 on the servo shaft 100 so as -to be raised progressively as the propeller pitchis increased in either direction from zero. The shape of the cam surfaces and therefore the ratio of transmission of the restoringmotion determines the increment-ofpropeller pitch change for a given change in the position of the lever 194 and therefore in the position of the control lever 78.

With the parts thus arranged, raising of the stem 182 will swing the lever 194-about the rod end 199 as a fulcrum thus lowering the stern of the pilot valve out of the centered position shown in Fig. l. Pressure uid is thus admitted to the passages 192 and 151 and the servo chamber 103 while the passages 191 and 146 are connected to the drain thereby initiating an increase in the propeller pitch which continues until the rod 196 has been moved far enough to restore the centered position of the valve 185. Conversely, a lowering of the follower 182 causes the valve plunger 186 `to be raised to admit pressure fluid through the passages 191 and 146 to the other servo chamber 102, the chamber 103 being at the same time drained. As a result, the propeller pitch is decreased until the valve is recentered by the follow-up motion.

Similar pitch adjusting action but in the different ranges takes place in response to movement of the hand lever 78 to either side of the zero or flat pitch position. This isfor the reason that, as described above, the transfer valve 122 remains in the forward position (Fig. l) when the hand lever is disposed in the forward range and is shifted by the servo 127 to the reverse position (Fig. 2) when the hand lever is turned clockwise to condition the propeller for backward movement of the ship.

.This PPaOn s a division of my copending application Serial No. 412,324 tiled Feb. 24, 1954, now Patent No. 2,878,880.

I claim as my invention:

1. The combination of, an adjustable pitch propeller, a fluid pressure servo having two pressure chambers and a piston element movable in opposite directions away from a flat pitch position through forward and reverse pitch ranges of a control valve for regulating the admission of pressure uid to and the escape of the uid 'from a selected one of said chambers, means controlled by said element for maintaining said propeller at zero pitch when the element is in said tiat pitch position and for increasing the pitch in forward and reverse directions respectively and in proportion to the movements of said element in opposite directions away from said fiat pitch position, stop means for confining the movement of said piston element to a distance correspondig to the length of one of said pitch ranges, a support carrying said stop means and movable between two positions in one of which the movement of said element is confined to said forward range and in the other of which the element the movement of said element is confined to said forward range and in the other of which the element movement movement is limited to said reverse range, a second v servo energizable selectively to move said support between said two positions and hold the selected position against the force of said tirst servo, and a transfer valve having a member movable between two positions in one of which said control valve is associated with one of said chambers and said second servo is energized to shift said stop support to a corresponding one of the stop positions, said transfer valve in its other position associating said control valve with the other of said chambers and energizing said second servo to hold said stop support in its other position.

2. The combination of, an adjustable pitch propeller, a uid pressure servo having two pressure chambers and a piston element movable in opposite directions away from a flat pitch position through forward and reverse pitch ranges and the position of said element in each of said ranges, means controlled by said element for maintaining said propeller at zero pitch when the element is in said flat pitch position and for increasing the pitch in forward and reverse directions respectively and in proportion to the movements of said piston element in opposite directions away from said liat pitch position, two stops spaced apart a distance corresponding to the lengths of the individual forward and reverse pitch ranges of said piston element, a support carrying said stops and movable between two positions in one of which is limited to said reverse range, and a second servo energizable selectively to move said support between said two positions and hold the selected position with a force greater than that developed by said first servo.

3. The combination of, an adjustable pitch propeller, a servo having a driven element movable in opposite directions away from a at pitch position through forward and reverse pitch ranges, means controlled by said element for maintaining said propeller at zero pitch when the element is in said at pitch position and for increasing the pitch in forward and reverse directions respectively and in proportion to the movements of said element in opposite directions away from said flat pitch position, stop means for limiting the movement of said driven element a distance corresponding to the length of one of said pitch ranges, a support carrying said stop means and movable between two positions in one of which the movement of said element is conned to said forward range and in the other of which the element movement is limited to said reverse range, and a second servo energizable selectively to move said support from one of said positions to the other and holding the selected position against the force of said lirst servo.

4. The combination of, an adjustable pitch propeller, a uid pressure servo having two pressure chambers and a piston element movable in opposite directions away from a fiat pitch position through forward and reverse pitch ranges, means controlled by said element for maintaining said propeller at zero pitch when the element is in said iiat pitch position and for increasing the pitch in forward and reverse directions respectively and in proportion to the movements of said element in opposite directions away from said tlat pitch position, stop means for confining the movement of said piston element to one of said ranges, a support carrying said stop means and movable between two positions in one of which the movement of said element is confined to said forward range and in the other of which the element movement is limited to said reverse range, and a second servo energizable selectively to move said support between said two positions and hold the selected position thereof with a force greater than that developed by said first servo.

References Cited in the file of this patent UNITEDy STATES PATENTS 2,455,378 McCoy Dec. 7, 1948 

